From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Extract from a report suggesting a second ignition coil as a standby instead of a magneto for the 20 HP car.
| Identifier | ExFiles\Box 54\5\ Scan317 | |
| Date | 4th December 1929 | |
| X5680 Extract of report EFC {E. Fowler Clarke - Electrical Engineer} 2/AD4.12.29. K5792 We have the impression that the provision on the 20 HP. of complete dual ignition as on the Phantom II has been given some consideration. This, we believe, has been strongly advocated by some. We would like to recommend the consideration of an alternative suggestion, namely to provide a second ignition coil as a standby instead of a standby magneto. The following reasons are given in support of this :- (1) Such ignition failures as do occur are almost invariably now those of ignition coil windings. The possibility of such failure appears, so far as we can ascertain, to be an accepted matter with other makers of coils. N.B. We are working to eliminate such failure as entirely as possible by the improvement of the mechanical and electrical construction of our coil. (2) It would be possible to switch from one coil to the other by means of a double pole changeover switch placed near the coils, and electrically in the primary circuit only, thus considerably simplifying the changeover to standby ignition. The switch could be of specially attractive bakelite design, and being placed near the coils there would be no alteration to the remainder of the wiring system. The two high tension ends, one of each coil, could both be permanently connected to the distributor and each coil when not on duty would be "floating" on the high tension lead. It has been confirmed by trial on the bench that this arrangement behaves satisfactorily as expected. (3) Batteries may be considered to be very much better than at the time the original arguments for the standby magneto ignition were put forward, also, in general, less likely to be abused. (4) The two difficulties (a) Of starting and (b) Of insufficient range of magneto would be eliminated. (5) There would be considerable saving in cost and the additional advantage that the whole of the ignition apparatus would be R.R. design and manufacture. EFC. {E. Fowler Clarke - Electrical Engineer} | ||